How Sludge Can Save The World

Sludge. It’s slimy, filthy, smelly and disgusting – but that’s just what most people think.

On the surface, sludge appears as useless waste in slimy, saturated form, but underneath all these seemingly unpleasant features, sludge is actually quite beneficial, and can even be considered as contributory to helping the earth conserve and preserve resources.

What is Sludge?

But what exactly is sludge? Essentially, sludge is what remains after industrial wastewater treatment or sewage treatment (apart from effluents or treated wastewater). During these treatment processes, wastewater recovered from domestic as well as industrial processes are collected and the solids are separated from as much of the liquid as possible, forming the slurry we know as sludge.

Because of its highly varied composition and the many processes it undergoes including anaerobic decomposition, sludge is packed with all kinds of things, including numerous nutrients, metals, pathogenic organisms and various other chemicals.

Also known as biosolids or compost, sludge is not considered a pollutant though some studies have shown that it can be potentially harmful to human health due to the pathogens, metals and other chemicals present within it.

How Sludge Supports the Environment

Despite essentially being made up of waste, sludge is highly beneficial and can be a very valuable resource that can help save the world in more ways than one. While it’s long been used as landfilling material, sludge is now gaining more recognition as the following:

• All-natural fertiliser – According to a study with the Texas Agricultural Extension Service, common sewage sludge generally contains most of the nutrients considered vital to plant growth. These nutrients include nitrogen, phosphorous, magnesium, calcium, potassium, sulphur, copper, zinc, nickel, chromium and selenium. These nutrients are released slowly in sludge, and with the addition of sludge soil becomes more able to hold and absorb nutrients. Sludge also helps lessen erosion and natural soil runoff. The application of sludge as plant fertiliser then proves to be most beneficial for it not only enriches the earth and supports long-term and healthy plant growth, it also conserves organic matter; and the bacteria and nutrients present within sludge help to complete the nutrient cycle.


• Source of sustainable power – Another developing use for processed sludge nowadays is as fuel for energy production. In the US as well as in Sweden various groups are actively making more use of sludge as a source of sustainable power by turning it into steam, using it in place of coal, and producing electricity, biogas and other such fuels. This has been proving most efficient in some areas of the world, as these processes, particularly steam production, require less drying of sludge and therefore less energy. Studies have also shown that processed sludge or biosolids had lesser levels of contaminants than coal, making it a better choice for incineration. Because of these developments, more wastewater treatment plants are being set up and working together with communities and governments.

With the amount of wastewater produced and treated every year resulting in hundreds of tons of sludge, it is definitely the ideal time to consider the usefulness of sludge. Though many are still apprehensive about the secondary uses of sludge because of the harmful elements still present in it as well as the many stringent rules regulating its use, modern treatment methods and technologies are constantly being developed to ensure that the reuse of sludge produces limited to no harmful effects to the environment. With these developments, sludge will slowly but surely become a vital resource, quite literally turning waste into valuable and useful materials that can help save the earth.

 

By Debra Wright

Debra Wright is a creative and innovative blogger and online marketing specialist. She uses her wordsmith skills to share her ideas, thoughts, and tips to other people about topics that fascinate her, such as environmental issues. Follow Debra on twitter @debrawrites…

How Sludge Can Save The World